Filament mounting



Jime 2, 1931. w. WEINGARTNER 1,807,885

FILAMENT MOUNTING Filed Aug. 51. 1929 INVENTOR w. WEI/vc AR TNER TTOR Patented June 2, 1931 UNITED STATES PATENT OFFICE WILLIAM WEINGARTNER, OF IRVINGTON, NEW JERSEY, ASSIGNCSR TO WESTINGHOTEISE,

LAMP COMPANY, A CORPORATION OF PENNSYLVANIA FILAIVIENT MOUNTING Application filed August 31, 1929. Serial No. 389,697.

This invention relates to incandescent lamps, electron discharge devlces, gas discharge devices and the like electrical devices employing an incandescent filament and more 5' particularly relates to the method of mounting said filament in said devices, and has for its object the provision of a method of mounting and supporting the filament in a substantially strain free position, so that subsequent distortion during operating life is substan- 1 5 such as electron discharge devices, wherein to facilitate the manufacture and assembly the incandescent filament is employed as an I electron emitting cathode in cooperation with one or more associated electrodes.

Another object of the presentinvention is of electric devices employing an incandescent filament.

Other objects and advantages will become apparent as the invention is more fully dis- In accordance with the objects of my invention I have found that a large proportion of the deleterious distortion of a metal filament mounted in accordance with prior art practices has been due to the mechanical stresses and strains applied to the filament during the mounting operation, which tend to distort the filament from its preformed condition;

"It is customary in the manufacture of electric devices such as incandescent lamps, electron discharge devices and the like employing segmented type filaments, particularly filaments of the tungsten class, to preform the said segmented filament. Subsequently the preformed V, W or M shaped filament is mounted within the device. 7 i

During such mounting the legs of the filament are attached to'the filament support members at the desired points, with little regard to the pre-formed spacings imparted thereto, with a consequence that mechanical st'ressesand strains are set up in the filament. With filaments of the tun sten'class wherein the elongated cold worke grains of the fila=- ment are subjected to recrystallization upon incandescence, the rate of said recrystallization and the direction ofgrain growth is materially effected by the application of mechanical stresses or strains. As a-result of grain recrystallization while under strain the filament becomes displaced from its mounted position. Such phenomena is usually spoken of as sag, twist and the like terms.

' In electron discharge devices such as radio tubes, power tubes; rectifier tubes and the like devices, displacement of the incandescent filamentary cathode alters the spacing of the cathode from the cooperating electrodes of the device, thus causing variations in the electrical characteristics of the device. -It is highly essential that in such devices this al.-

teration of cathode spacing and alignment I during assembly, manufacture and use he reduced to the minimum. Y

Before further disclosing the nature of my invention reference should be had to-theaccompanying drawings wherein is shown in Fig. 1 a front elevational fragmentary view of a filament mounted in accordance with the present invention.

Fig. 2 is a side elevational'view of the same.

Fig. 3 is a front elevational view of the device I employ in the mounting of filaments to obtain definite strain free spacing therein; and

Fig. 4 is a side elevational view of the fila ment spacing member shown in Fig. 3, showthe spacing of the cooperating electrodes is very closeand any displacement in the alignment of the cathode materially alters the plate current of thedevice. j

It is customary in such a device 'to employ two inverted V sha ed filaments I and 2 connected electrically in parallel with a central support member 3 having tensional spring members 4 and 5 at the top engaging the V of the filament.

Heretofore it has been exceedingly difficult to mount these filaments so that they are substantially vertically parallel, and parallel also to the central, support. member 3'. It

has also been difficult to obtain such a mounting of the two inverted V shaped filaments so-that" no mechanical stress or strain is imparted thereto.

I effect this in the following novel manner by providing an inverted U shaped filament support member 6 such asv is shown in Fig. 3, which is comprised preferably of molybdenum as; this highlyrefractory m al n the sizes .employedjmay be more readily shaped and subsequently we ded to the filam nt than may tungsten-l: The ute parallel dge 7 and 8- ofthe U are ground off or other attened. e

for the leg of the-support member to rest upomtightly Wrapping the two together with molybdenum wire, and thenare welding the. union together.

The two U connectors are mounted upon the leadingi-n filament support wires in such manner as to present parallel edges and they may then be adjusted so as to be equidistant from the center support wire 3 at a distance approximately equal to the inside distance between the two legs of the preformed inverted V shaped filaments l and and in a vertical plane parallel to the upper spring support suspension members 4 and 5. This position places the flattened edges '7 and 8- of theUconnector in such position that one leg offilament 1 and one leg of filament 2 fallf'adjacentthe flattened surfaces 7 and 8 of the said U support member when the filamentsare vertically suspended from spring suspension members 4 and 5. 1

By making the distance between the, two flattened surfaces of the .U connector approxi mately equal to the distance A between points 12 and 13 (Fig. ,1) on spring suspen-. sion members 4 and 5 when said filaments 1 and 2 are vertically suspended'therefrom, the aligning of the filament legs in a substantially vertical position and in parallel relationship to .each other is a matter of relative simplic- In this method of filament mounting @the deleterious effects due to mounting stresses and strains imparted to the filament throng-h mechanical displacement of the filament legs from their preformed positions, is substantially eliminated as may be noted in Fig. 2, wherein is shown how the U connectors 6 and 6 have been adjusted so thatthe distance justed the legs of the filaments 1 and 2 are electrically connected to the surfaces of the U connector i a y e re manner uch a by arc welding and the assembled mount is ready to be incorporated in an electron dis,- charge dev ce.

It is apparent that there may be many variations and departures from the specific embodiment herein disclosed without essen.- tially departing from the nature of the present invention and such departures and variations are anticipated as may fall Within the scope of the following claims:

What is claimed is: I

1. In a filament mount-employing preformed twin inverted V-shaped filaments in spaced parallel relationship and electrically connected in parallehmeans for setting up a substantial strain free parallel spaced relationship and parallel electrical connection. with leading in wires of the filament mount which comprises twininverted U-shaped filament connectors integral with the filament.

lead wires of said filament mount, said U; connectors being spaced in parallel relationship in vertical planes apart substantially a distance equal to the distance apart of the ends of the preformed filament legs, and in a plane at right angles to the plane of said parallel filaments, the outer edges of the legs of said U connector being shaped to-present parallel surfaces in the same vertical plane as the apex of. said mounted preformed fila-v me tp 2. In a filament mount'comprising a flare tube terminating at one end in a press, leading in wires passing through said press, a filament support member integral at one end with said press intermediate said lead wires,

resilient spring suspension members oppositely disposed at the other end of said support member, twin inverted V-shaped filaments suspended frolnsaid suspension mem-. bers, means for pos tioning said twin fila ments in parallel spaced relationship and electrically connecting the legs thereof in parallel comprising an inverted U-shaped connector'member integral with the ends of the leading-in wires passing through said press, said U connectors being positioned so as to lie vertically in planes parallel to the.

plane of, said spring suspension membe s, a d

WILLIAM WEINGARTNER. 

